Paper Cup

ABSTRACT

The present invention relates to a paper cup comprising a sidewall member having an upper edge, a lower edge, a pair of opposite side edges, a front surface and a back surface, each of the side edges and the upper edge defining upper corners, the side edges being overlapped and sealed together along an overlapping side seam, and a bottom member having a peripheral lip sealed to the lower edge of the sidewall member; said paper cup is remarkable in that it further comprises at least one rigid or semi-rigid rim structure attached to the upper edge of the side wall member and in that the paper weight of the bottom member is greater than the paper weight of the sidewall member.

FIELD OF THE INVENTION

The present invention relates generally to paper cups coated with thermoplastic, and more particularly, pertains to paper cups intended to drinks vending machine or similar.

BACKGROUND OF THE INVENTION

It is well known that polystyrene cups are commonly used in hot or cold drinks vending machine because polystyrene cups are inexpensive and present softness essential for vending machines.

The insulating properties of the outer walls of polystyrene cups and stiffness of its upper rim allow the cup to be comfortably held despite the high temperature of its contents.

The disadvantages of polystyrene cups are that it is not biodegradable, readily recycled or microwavable.

In contrast, paper cups are both recyclable and biodegradable, but such cups, using a single sheet of paper for their outer walls, provide little thermal insulation, present a side edge having a stiffness too high for a use in a vending machine, and is too expensive.

A number of ways to enhance the insulating characteristics of paperboards from which the hot cups are made have been developed.

One such paperboard is disclosed in U.S. Pat. No. 7,056,563, wherein the insulating paperboard comprises at least one layer having cross-linked fibber therein to enhance the thickness and thus the insulating characteristics of the paperboard.

Other strategies have been tried to address the problem of heat transfer through a paper cup.

One way to address this problem is to double cup. However, double cupping not only increases costs, but it also increases the amount of waste that is produced and the stiffness of paper cups.

There have also been attempts to design insulating holders that are reusable, especially for cold beverages.

Nevertheless, none of these paper cups provide a sufficient softness to be used in a vending machine. Moreover, these paper cups are cost expensive and cannot be comfortably held despite the high temperature of its contents.

Therefore, a need exists for an improved inexpensive paper cup and providing a sufficient softness to be used in a vending machine.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a paper cup comprising a sidewall member having an upper edge, a lower edge, a pair of opposite side edges, a front surface and a back surface, each of the side edges and the upper edge defining upper corners, the side edges being overlapped and sealed together along an overlapping side seam, and a bottom member having a peripheral lip sealed to the lower edge of the sidewall member; said paper cup further comprises at least one rigid or semi-rigid rim structure attached to the upper edge of the side wall member and in that the paper weight of the bottom member is greater than the paper weight of the sidewall member.

The paper weight of the bottom member is comprised between 240 and 400 gsm and the paper weight of the sidewall member is comprised between 150 and 240 gsm.

In a first embodiment, the rim structure consists in a ring enclosed in a rolled upper edge.

In a second embodiment, the rim structure consists in a ring hounded onto the back surface of the sidewall member near its upper edge.

Said rim structure can be a plastic and/or metallic ring.

Preferably, the sidewall member has a generally trapezoidal shape suitable to form a tronconical paper cup and the rim structure is an annular ring.

Accessorily, the back surface and/or the front surface of the sidewall member and/or the bottom member is coated with a biodegradable film.

Said biodegradable film is made by Plolyactic Acid (PLA), bio-Polymers or bio-degradable plastic suitable to be composted.

Moreover, the front surface of the sidewall member can be at least partially embossed to form relief.

Other features and advantages of the invention will become apparent to those skilled in the art during the description which will follow, given by way of a non-limiting example, with reference to the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective exploded view of a paper cup according to the present invention;

FIG. 2 is a cross section view of paper cup according to the invention;

FIG. 3 is a cross section view of a second embodiment of the paper cup according to the invention;

DETAILED DESCRIPTION OF EMBODIMENTS

In the various figures, the same references are used to designate identical or similar elements.

Referring to FIGS. 1 and 2, the paper cup comprises a sidewall member 1 having an upper edge 2, a lower edge 3, a pair of opposite side edges 4,5, a front surface and a back surface, each of the side edges 4,5 and the upper edge 2 defining upper corners. The side edges 4,5 are overlapped and sealed together along an overlapping side seam 6. Moreover, the paper cup comprises a bottom member 7 having a peripheral lip 8 sealed to the lower edge of the sidewall member 1.

The paper cup according to the invention further comprises a rigid or semi-rigid rim structure 9 attached to the upper edge of the side wall member.

In this particular embodiment, the sidewall member 1 has a generally trapezoidal shape suitable to form a tronconical paper cup including a curl 10 at the top of the cup, said paper cup being made with a typical cup machine.

A typical cup machine for making paper cups, for instance, includes a turret having a plurality of mandrels about which the containers are formed. The turret sequentially rotates the mandrels into cooperation with a variety of workstations where numerous cup forming procedures occur.

In an exemplary procedure, a circular bottom member is cut out at one workstation and attached to the end of a mandrel by a vacuum applied through the mandrel. During this procedure, the outside edge or lip of the bottom member is folded downwardly. At a subsequent workstation, a sidewall member is wrapped around the mandrel. The sidewall member is heated and sealed along an overlapped side seam which runs generally longitudinal along the side of the cup. Typically, a paperboard is coated with a thermoplastic material such as polyethylene or a solid plastic sheet can be used, so the bottom and sidewall members may be heated and sealed together. In some applications, the sidewall member includes a flap 11 extending beyond the lip 8 of the bottom member, and this flap 11 is bent over the lip 8. At a bottom finishing station, the flap 11 is pressed against the lip 8 from an inside recessed area of the bottom of the cup. By heating the polyethylene and firmly pressing the sidewall, sidewall flap, and bottom flap lid together, a bottom seal is formed and the cup is provided with a sturdy bottom region having a recessed area. There may also be other work stations where various other additional cup forming procedures are carried out. For example, one station may be used to provide a curl 10 at the top or rim of the cup to provide a more functional drinking container and a better appearance.

During this procedure, a rim structure consisting in a rigid or semi-rigid ring 9 is positioned on the top of the cup in such a manner that said ring 9 is finally enclosed in the rolled upper edge forming the curl 10. Said rim structure can be a plastic and/or metallic ring. Nevertheless, said rim structure can be obtained in any suitable rigid or semi-rigid material without departing from the scope of the invention.

It should be noted that the rim structure 9 rigidifies the top of the paper cup allowing a user to hold it from the top between its thumb and its forefinger without crushing it.

Moreover, the paper weight of the bottom member is greater than the paper weight of the sidewall member. For instance, for a cold or hot drink paper cup, the paper weight of the bottom member is comprised between 240 and 400 gsm (grams per square meter) and the paper weight of the sidewall member is comprised between 150 and 240 gsm. In this way, the paper cup according to the invention provides a sufficient softness allowing a use in a vending machine and can be comfortably held despite the high temperature of its contents. Furthermore, by using a lower paper weight for the sidewall member 1, the unit cost production of the paper cup is lower than a traditional paper cup and is close to the unit cost production of a plastic drinks cup.

Advantageously, the back surface and/or the front surface of the sidewall member and/or the bottom member is coated with a biodegradable film to ensure the impermeability of the cup and/or the sealing of the bottom and sidewall members. Said biodegradable film can be made by Plolyactic Acid (PLA), bio-Polymers or bio-degradable plastic suitable to be composted.

Accessorily, the front surface of the sidewall member 1 is at least partially embossed to form relief, not shown on figures. Said relief decreases the contact area between the user's hand and the cup in such a way that the cup can be comfortably held despite the high temperature of its contents.

According to a second embodiment of the paper cup according to the invention, referring to FIG. 3, the paper cup comprises in the same manner as previously a sidewall member 1 having an upper edge 2, a lower edge 3, a pair of opposite side edges 4,5, a front surface and a back surface, each of the side edges 4,5 and the upper edge 2 defining upper corners. The side edges 4,5 are overlapped and sealed together along an overlapping side seam 6. Moreover, the paper cup comprises a bottom member 7 having a peripheral edge 8 sealed to the lower edge of the sidewall member 1.

The sidewall member 1 has a generally trapezoidal shape suitable to form a tronconical paper cup including a curl 10 at the top of the cup, said paper cup being made with a typical cup machine. Said sidewall member includes a flap 11 extending beyond the lip 8 of the bottom member, and this flap 11 is bent over the lip 8. The flap 11 is pressed against the lip 8 from an inside recessed area of the bottom of the cup.

The paper cup according to the invention further comprises a rigid or semi-rigid rim structure 9 attached to the upper edge of the side wall member.

The rim structure consists in a ring bounded by any appropriate means onto the back surface of the sidewall member 1 near its upper edge, i.e. near the upper curl 10. Said ring is made in rigid or semi-rigid plastic and presents an annular shape.

It is obvious that the paper cup according to the invention can present different shapes, as a tronconical shape, an ovoid shape, a parallelepipedic shape, a trapezoidal shape, etc, the rigid or semi-rigid rim structure 9 having a corresponding shape such as a circular, ovoid, rectangular or squared shape without departing from the scope of the invention.

Moreover, the paper cup according to the invention can find a large range of applications in the food and drink industry, and can be used as a container for yoghurt or any microwavable food (pastas, rice, etc) for example.

Any reference sign in the following claims should not be construed as limiting the claim. It will be obvious that the use of the verb “to comprise” and its conjugations does not exclude the presence of any other elements besides those defined in any claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. 

1. A paper cup comprising a sidewall member having an upper edge, a lower edge, a pair of opposite side edges, a front surface and a back surface, each of the side edges and the upper edge defining upper corners, the side edges being overlapped and sealed together along an overlapping side seam, and a bottom member having a peripheral lip sealed to the lower edge of the sidewall member, characterized in that it further comprises at least one rigid or semi-rigid rim structure attached to the upper edge of the side wall member and in that the paper weight of the bottom member is greater than the paper weight of the sidewall member.
 2. The paper cup according to claim 1, characterized in that the paper weight of the bottom member is comprised between 240 and 400 gsm.
 3. The paper cup according to claim 1, characterized in that the paper weight of the sidewall member is comprised between 150 and 240 gsm.
 4. The paper cup according to claim 1, characterized in that the rim structure consists in a ring enclosed in a rolled upper edge forming a curl.
 5. The paper cup according to claim 1, characterized in that the rim structure consists in a ring bounded onto the back surface of the sidewall member near its upper edge.
 6. The paper cup according to claim 1, characterized in that the rim structure is a plastic and/or metallic ring.
 7. The paper cup according to claim 1, characterized in that the sidewall member has a generally trapezoidal shape suitable to form a tronconical paper cup and in that the rim structure is an annular ring.
 8. The paper cup according to claim 1, characterized in that the back surface and/or the front surface of the sidewall member and/or the bottom member is coated with a biodegradable film.
 9. The paper cup according to claim 8, characterized in that the biodegradable film is made by Plolyactic Acid (PLA), bio-Polymers or bio-degradable plastic suitable to be composted.
 10. The paper cup according to claim 1, characterized in that the front surface of the sidewall member is at least partially embossed to form relief. 